This invention relates to a clock with laterally openable dial pieces.
Most conventional clocks have stationary dial plates. For example, in gimmicky clocks of the type in which a door opens at a given time to exhibit a decoration, such as doves or dolls, the decoration is exhibited in a space not overlapping with a dial plate and the dial plate is held stationary.
The present applicant has proposed a clock which is characterized in that a mobile decoration such as a doll or the like is disposed behind of dial pieces, and these dial pieces are laterally opened at a given time to exhibit such a decoration. See Japanese Patent Application No. 63-311614. The mechanism of opening and closing the dial pieces in the prior application is characterized in that a lead screw is rotated by a driving motor rotatable in both directions, a female nut is shifted along the lead screw upon rotation thereof, and the shifting of the nut is transferred via a link mechanism to the dial pieces to open and close them.
In such a system as described above, a driving motor rotatable in both directions must be used to open/close the dial pieces. In addition costs increase, two position detecting switches are necessary to detect the open/close state of the dial pieces, and a large space is required to accommodate a dial piece opening/closing mechanism. Further, more when the dial pieces are to be opened, a heavy load is imposed on the motor, and when they are closed, the weight of the dial pieces acts to promote the rotation of the motor, and thus, a counter electromotive force is generated in a circuit, which has negative influence on the circuit. Additionally, the interval of time necessary for the dial pieces to close is shorter than the interval of time necessary to open, and such imbalance in operation time maker for an appearance which is inferior.